1. Field of the Invention
The present invention generally relates to a circuit structural design for an antenna, and more particularly to a circuit structural design for a headset antenna.
2. Description of Related Art
Headset antennas are widely used in mobile broadcast, especially in receiving operation of frequency modulation (FM) broadcast. Currently, headset antennas are also employed in mobile television field for improving signal receiving efficiency thereof.
In a typical headset antenna, an audio signal line and an antenna are often integrated in a headset wire. Therefore, signals received by the antenna attenuate due to a coupling effect of adjacent lines. That is so because, the audio signal line is equal to a ground at the specified frequency band of the RF (Radio frequency) signal, so that receiving capability of the antenna is weakened due to the adjacent audio signal lines. This is also a main factor restricting the receiving capability of the current conventional headset antennas. However, most current headset antennas are designed to improve the receiving capability by employing post power amplifiers, instead of providing a corresponding solution.